void main(List<String> args) {
  bool showSheet = true;
  if (showSheet) {
    print('显示');
  } else {
    print('隐藏');
  }
  // 三元运算符
  showSheet ? print('显示') : print('隐藏');

  int count = 10;
  bool isOk = count == 0;
  print(isOk);
}
